In electrophotographic printing, an electrostatic latent image is formed on a photoreceptive surface, and then developed by application of charged toner particles to the image. The resulting toner image is fixed and transferred onto a surface that is to hold the permanent image. The quality of printed electrophotographic images depends at least in part upon the efficiency of development, i.e. how well the available toner is incorporated into the toner image to create a faithful representation of the latent image. Inefficiency in this process can arise from ineffective charging and discharging of individual toner particles or the toner pool as a whole. One result is incomplete development due to failure of poorly charged toner to be incorporated into the toner image; and another can be failure of incorporated particles to be transferred from the photoreceptive surface. Both of these phenomena lead to printed images of inferior quality. An additional concern is the phenomena of “pollution” of the toner pool, i.e. a gradual erosion of printing efficiency over time due to a progressive decrease in the ratio of suitable toner particles to inferior ones. This inefficiency decreases the output capacity of each batch of toner and can result in costly waste over the service life of a printer.
Electrophotographic printing applications can derive benefits from methods and compositions that increase the efficiency and overall effectiveness of the underlying processes. Such benefits include better print quality, longer service life, and greater cost effectiveness.